I wouldn't consider myself a good player being quite casual and I learn better by doing rather than watching videos/reading guides so it always takes me a couple of attempts to learn a mechanic (and heck, there's still mechanics in-game I struggle with) but I would say that wasn't the hardest fight in the game.
Granted took three attempts to beat it the first time around (manly due to other party members dying to mechanics) but we got it together and had it completed within 30 minutes. I'd agree with most other responses though - after 90 levels you shouldn't be struggling too much that fight (unless you boosted which tbh - no new player should really do and I never understand why they would), there's certainly harder ones along the way.